What does it mean when we say an object is three-dimensional? If you slice a 3D sphere, what kind of shape will you see inside? If you slice a square diagonally, what kind of shape do think that you'll end up with? What are some examples of three-dimensional shapes? What are examples of three-dimensional objects that are spheres, cubes, and cylinders?

How is a plane section different from a cross section? What are the different directions a cross section of a figure can be sliced? What are some hints we can use to figure out what a cross section of a figure will look like? Which three-dimensional figures could be sliced into three totally different shapes? What are some 3D shapes that you could slice to make a circle, a stretched hexagon, and a rectangle? What are the three major planes that you can use to slice objects and discover 2D cross-sections?